The Pediatric Heart Disease Clinical Research Network will be a cooperative network of up to six Clinical Centers, a Data Coordinating Center (DCC), and the Division of Heart and Vascular Diseases of the NHLBI. The specific aim of this network is to efficiently conduct multi-center clinical studies (including but not limited to randomized clinical trials), and to evaluate new and existing treatments and management approaches for children with structural congenital heart disease, inflammatory heart disease, heart muscle disease, and arrhythmias. The role of the DCC is to support protocol development for the clinical studies, to provide statistical design expertise, to identify, train, and maintain central laboratories for echocardiography and other cardiac specialties; to collect and monitor the data and provide quality assurance in the form of personnel training and site visits; to provide overall study coordination including plans for patient recruitment and retention; and to analyze the data collected and promote rapid dissemination of study findings. New England Research Institutes (NERI) proposes that in the first year of Network funding, that patient registries of the cardiac conditions most likely to be the focus of Network studies be established in order to facilitate patient recruitment at the time of study approval and a system of modular data collection forms be developed that can be selectively utilized by Network studies in later years to ensure efficient start-up. Data collection and data management for all studies will be conducted using NERI?s proprietary web-based system ADEPT (Advanced Data Entry and Protocol Tracking System). Sites will have immediate access to site-specific enrollment reports, patient follow-up reminders and data summaries on each study participant, NERI proposes a stepwise approach with objective criteria for the selection of core laboratories and offers key personnel with medical training for implementation of quality assurance procedures. Experienced research staff from NERI will coordinate both shipments and electronic submissions of laboratory specimens and diagnostic cardiac data for the core laboratories. The NERI statistical team has extensive experience in the field of cardiology will provide expert guidance in the design of both observational studies and randomized trials, including design of early stopping rules, This application also includes a proposal for collection of cost-effectiveness data to be analyzed by NERI?s health economist. NERI has extensive experience in all areas of multi-center study coordination and, more specifically, currently coordinates one of the only such studies in the field of pediatric cardiology, the Pediatric Cardiomyopathy Registry.